Various types of vehicle alert systems are known in the prior art. However, what has been needed is a vehicle occupant detection system including at least one weight sensing pad, at least one infrared sensor, and at least one motion sensor disposed within an automobile. What has been further needed is for each of the at least one weight sensing pad, the at least one infrared sensor, and the at least one motion sensor to be in operational communication with each of a battery and a computer system of the automobile. Lastly, what has been needed is for the computer system to be configured to activate at least one of a horn, an alarm, an engine, at least one power window, a wireless communication with a remotely disposed fob, a wireless text communication with a remotely disposed personal electronic device, and a cellular communication with an emergency responder when at least one of the at least one infrared sensor, the at least one weight sensing pad, and the at least one motion sensor detects a passenger disposed within the vehicle. The vehicle occupant detection system is thus uniquely structured to wire directly into a computer system of an automobile in order to prevent children and pets from being accidentally left in the automobile in extreme temperatures.